Apparatus for treating liquids with gases



w.- E. GHEENAWALTL APPARATUS FOR TREATING LIIIQUIDS WITH GASES. APPLICATION FlI- ED'0CT-30,1915-' RENEWED FEB. 12,1920.

1,374,500. A v PatentedApr. 12,1921.

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- UNITED STATES {PATENT OFFICE.

WILLIAM E. enEEir'AwAn'r; or DENVER, coLoRAno-f APPARATUS FOR TREATING LIQ'UTDS WITH GASES.

To all whom it many concern Be it known that'I, \VILLIAM E. GREENA- WALT, a citizen of the United States, resid ing in the city and county of Denver and State of Colorado, have invented certain new anduseful Improvements in Apparatus for Treating Liquids with Gases, of which the following is a specification.

The invention has for its more immediate object the effective application of gases to liquids to accomplish certain results, as, for example, the. precipitation of metals from their solutions by a gas-such as hydrogen sulfid, or in the flotation treatment of certain ores. It is not intended, however, to

- limit it to any particular use, although in describing the apparatus the above mentioned uses will be kept more or less in mind.

Thisapplication may be regarded as an improvement in part thereon of my pending applications, Serial No; 812,951, filed January 19, 1914, and S'erIal No. 845,011, filed-June 13, 1914.

Referring to the accompanying drawing, 1 is a tank containing a liquid and the material to be treated, 2 is a hood suspended within the tank and submerged in'the liquid, and having perforations 3, through which gases may be passed from the ins de 'of the hood to the liquid in the tank. 4 is a shaft, rotating on bearings 5, by means of which the hood is suspended and rotated wlthlnthe tank, when driven by the pulley (i. 7 1s a feed hopper, by means of which the material to be treated is fed into the tank. This feed hopper may vary in length, depending upon the material to be treated. Its bottom opening may be submerged in the liquid in treating some material, while for the treatment of other material it may be shortened, as shown, so as to deliver the material on the surface of the liquid in the center of the tank. 8 is a pipe, preferably stationary, through which air or other gas may be delivered to the submerged hoo( and havlng a regulating valve 10. Thepipe' 8 enters the mouth of the hood, and referably delivers the gas at a point above t e highest perforation. so as to prevent the liquid from entering the pipe, although if the liquid did enter the pipe no particular harm would be done. as it would again be expelled by the air or gas. 11 is an opening in the bottom of the tank through which the treated material may be removed by passing it through the pipe 12 and regulating valve 13. If de- Specification of Letters Patent.

Patented Apr. 12, 1921.

Application filed October 30, 1915, Serial No. 58,748, ilenewcii February 12, 1920. Serial No. 358,130.

- troduced into the pipe 14 through the-pipe 17, thus making an air-lift of the pipe 14..

Clogging, in the opening 11, in the bottom of the tank 1, is removed or prevented by an air or water jet introduced through the pipe 18. 19 is a launder, through which the liquid in the tank ma overflow, or throu h which the products 0 the treatment may e removed. 20 is the launder outlet.

The operation of the apparatus will now be'described when used in the flotation of suitable ores. The tank is filled with water or ore sludge. The hood 2 is rapidly rotated by the pulley 6. The valve'10 is then opened and a r or other gas under pressure in the pipe line 9 is forced into the hood, through the pipe 8. The gas, so forced in, will displace a certain amount of liquid in the hood and escape through the perforations 3, but

in escaping through the perforations into the liquid of the tank, the gasis atomized in contact with the liquid, due to the rapid rotation of the hood. The speed at which the hood is rotated will vary accordin to the size of the hood and the material to e treated, but will usually be sex er-a1 hundred revolutrons per minute for large hoods and several thousand for the smaller sizes. The idea, in operating the apparatus, is to get the gas in an exceedingly fine state of subdivision,or in other words to atomize it, and atomize it 1 in the liquid. The finer the subdivision, the more effective the application of the as beliquid circulates quite rapidly with the hood,

in its immediate vicinity, the upper part of the liquid in the tank is also circulating,

but slowly, and will not be greatly disturbed.

The ore, crushed to a suitable degree of fineness, usually from 60 to 80 mesh, and

treated with suitable ingredients to facili tate flotation, such as oil and possibly acid,

is then introduced into the apparatus through the hopper 7. As already stated, the lower opening of this hopper may be submerged in the liquid, or suspended over the top. 'In any case the ore passes through the hopper and enters the liquid in the vicinity of the shaft, and as it descends, passesv the respective perforations in the hood, and comes in intimate contact with the atomizedair or gas. The mineral that will float rises to the surface and appears as a scum 21. The residue, which will not float, passes downwardly between the hood and the tank and enters the outlet 11, where it may be withdrawn through the pipe 12 and valve 13, or elevated through the pipe 14, for re-treatment in the same apparatus, or'for further treatment in a similar apparatus in series with it. The scum of mineral matter on the surface of the liquidin the tank, due to the centrifugal motion of the surface of the liquid, is continuously worked toward the launder 19 into which it overflows, and is removed from th launder through the outlet 20. If the apparatus is to be used to precipitate metals out of solution, say, to precipitate copper out of its chlorid or sulfate solution with hydrogen sulfid, the hydrogen sulfid is forced into the hood through the pipes 8 and 9, and its flow is "regulated by the valve 10. The hydrogen sulfid, escaping through the holes 3, in the rapidly rotating hood, is atomized in contact with the solution, and is effectively applied in such a way that all the hydrogen sulfid will be consumed. The copper solution is introduced into the hopper 7, and as it passes through the tank, comes in contact with the atomized hydrogen sulfid, so that the copper is precipitated as the sulfid while an equivalent of acid is regenerated. The solution, with the precipitate, passes into the bottom of the tank and out through the opening 11;

from there it can be conducted to a settling tank through the pipe 12 and the valve 13, or it may be returned to the tank for further treatment if the values are not all precipitated, through the pipes 14 and 15, or

it may be passed to another apparatus, in series, for further treatment, through the pipe 16.

The amount of liquid displaced in the hood by the air or gas is easily regulated by the number and size of the openings or perforations in the hood, and the amount of air or gas introduced. It is desirable to have the perforations near the top of the hood smaller and fewer in number than those nearer the bottom.

It will be observed from the drawing that there is no mechanical connection between the rotating hood and the pipe 8 through which the gas is introduced .into the hood. This is the preferred arrangement, for with a high rotary speed moving connections.

such for example as when the gas is introduced through a, hollow shaft, are exceedingly troublesome.

The gas, introduced through the mouth of the hood offers no mechanical trouble of any-kind, no matter what the speed of rotation may be. It is desirable, though not necessary, to deliver the gas above the high est perforation in the hood to act as an air seal, or cushion, when the gas in the hood gets low. This can easily be effected by the arrangement shown in the drawing, by having a long collar on the hood and the'shaft only part way inserted in this collar; If the liquid at the top circulates too rapidly'or is agitated too violently comparative quiescence may be obtained by the baffles 23.'

introduced into the hood, say not enough to fill the gas passages, then some liquid will, of course,- be ejected with the gas through the gas passages, and at times it may be desirable to operate the apparatus in this way.

It is evident that by regulating the inflow of gas throughtlie pipes 8 and 9, by the valve 10,;a very wide variation of operating conditions may be obtained. It would be an easy matter toejectonly gas through the gaspassages, or, by shutting off the gas entirely to eject only liquid, or, by varying the inflow of gas to eject .any desired mixture of gas and liquid,'or, by varying the size and position of the gassages to eject tably be ejected through the passages of the atomizer: in the normal operation of the apparatus, and this will usually be the best .way to operate it, for, better" results are obtainableby ejecting a mixture of the gas and liquid, than by ejecting either, orxboth, separately.

The apparatus is convenient if a gas other than air is to be used either as applied to precipitation, impregnation of a liquid, or as applied to flotation, for, if such gases are introduced through a hollow shaft, the mechanical connection between the stationary supply pipe and the hollow shaft, at a high rotary speed, is something of a problem. By means of this apparatus the entire diflicul'ty is easily overcome and perfect regulation is obtainable.

With some of the passages in the atomizer. as shown in the drawing, extending cient speed to finely from the central portion of the atomizer toward its periphery, the gas, or gas and liquid, is ejected with considerable violence through the gas passages mto the liquid in the tank, and a high degree of atomization is obtainable. If the gas supply is small there will be considerable suction in the passages to draw the liquid in through the lower extremity of the atomizer and forcibly ejecting it toward the periphery and into the liquid in the tank.

1. In apparatus for treating liquids with gases, a tank adapted to contain a liquid, a rotary member, having gas passages arranged with outlets at variable distances from the center and extending from its central portion toward its periphery, suspended within the tank andsubmerged in the liquid, and means arranged for introducing a gas into the central portion of the rotary member whereby liquid is displaced from the rotary member and gas is forced through the said passages.

2. In apparatus for treating liquids with gases; a tank adapted to contain a liquid; an atomizer having gas passages extending I from its central portion toward its periphery and having a continuity of exterior surface between the gas passages, suspended within the tank and submerged in the liquid, means for rotating the atomizer with sufiisubdivide the gas in the liquid, means for causing a flow of gas through the gas passages from the central portion toward the periphery.

3. In apparatus for treating liquids with gases, a tank adapted to contain a liquid; an atomizer having a circular periphery and arranged with gas passages extending from its central portion toward its periphery and having continuity of external surface between the gas passages, suspended within the tank and submerged in the liquid; means for causing afiow of gas through the gas passages from the central portlon of the atomizer toward its periphery; and means for rotating the atomizer about its axis with 'the center of the circular periphery as the center of rotation.

4c. In apparatus for treating liquids w th gases, a tank adapted to contain a liquid; an atomizer having a circular periphery and continuity of external surface and arranged with gas passages extending from its'central portion toward its peri hery, suspended within the tank and su merged in the liquid; means for causing a flow of gas through the gas passages from the central portion of the atomizer toward its periph; ery: and means for rotating the atomizer about its vertical axis with the center of the circularperiphery as the center of rotation, and with suflicient speed to finely subdivide the gas in the liquid.

sages 5. In apparatus for treating liquids with gases, a tank adapted to contain a liquid; an atomizer having a circular periphery and continuity of external surface concentric with the periphery and arranged with gas passages extending from its central portion toward its periphery, suspended within the tank and submerged in the liquid; means for causing a flow of gas through the gas pasfrom the central portion of the atomizer toward its periphery; and means for rotating the atomizer about its vertical axis with the center of the periphery as the center of rotation.

6. In apparatus for treating liquids withgases, a tank adapted to contain a liquid, a gas atomizer suspended within the tank and submerged in the liquid, means for introducing a 'gas in the lower portion of the tank to be atomized by the atomizer in its ascent through the liquid, and an air trap arranged to prevent the liquid from flowing into the gas inlet in the lower portion of the tank.

7. In apparatus for separating minerals from their gangue by flotation, a tank adapted to contain a liquid and the material to be treated, a rotary gas impregnator having a circular periphery and a porous top and arranged with an annular space between it and the sides of the tank, suspended within the tank and submerged in the liquid, means for introducing a gas into the tank thereby displacing liquid in the impregnator and forcing the gas through the porous top of the impregnator, means for rotating the'impregnator, and means'for feeding the material to be treated near the center of rotation and passing it across the path of the ascending atomized gas in the liquid.

8. In apparatus for separating minerals from their gan ue by flotation, a tank adapted to contain a to be treated, a rotary gas impregnator having a circular periphery and a porous top and arranged with an annular space between it and the sides of the tank, suspended within the tank and submerged in the liquid, means arranged for passing a gas through the submerged porous top of the impregnator into the liquid above it, means for rotating the impregnat-or, and means for feeding the material to be treated near the center of rotation and passing it across'the path of the ascending atomized gas in the liquid and downwardly through the annular space between the impregnator and sides of the tank. 1

9. Ina paratus for separating minerals from their gangue by flotation, a tank liquid and the material adapted to contain a liquid and the-material to be treated, a rotary gas impregnator having a circular periphery and gas passages .the path of the ascending atomized gas in the liquid and downwardly through the space between the rotaryimpregnator and the sides of the tank. Y

10. In apparatus for treating liquids with gases, a tank adapted to contain the liquid, a rotary atomizer comprising a hollow body open at its lower end and having attenuated discharge passages through its wall, said hollow body being journaled in the tank and submerged in the liquid, and means for admitting a regulable-quantity of gas under pressure to the hollow body.

11. In apparatus for treating liquids with gases, a tank adapted to contain the liquid, an atomizer comprising a hollow circular body submerged in the liquid and having attenuated discharge passages through the wall thereof, said hollow body having the lower portion, of its interior in communication with the tank, and means for introducing gas into the upper portion of the interior of said hollow body.

12. In apparatus for treating liquids with gases, a tank adapted to contain the liquid, a'hollow circular rotary body journaled on a substantially vertical axis within the tank and submerged in the liquid, said rotary body having discharge passages through its upper wall portion within the area of its circular periphery, a liquid inlet arranged below said discharge passages, and means for supplying gas to the interior of said hollow member.

13. In apparatus for treating liquids with j gases, a tank for containing liquid, a hollow rotary body journaled thereinon a substantially vertical axis and having discharge passages arranged at different elevations, said body having its lower part adapted to receive liquid from the tank, and means for supplying gas under pressure to the upper portion. of said hollow body.

14:. In apparatus for treatlngliquids w th gases, a tank adapted to contaln the liquid, a hollow rotary body journaled on a substantially vertical aXis within the tank and submerged in the liquid, said rotary body having radial discharge passages arranged at different elevations, and having its lower portion in communication with thetank, and means for supplying gas to the interior of said hollow body.

15. In apparatus for treating liquids with gases, a tank adapted to containthe liquid, a rotary hollow member submerged in the liquid and having an opening in its lower portion in communication with the tank, said rotary hollow member having discharge passages through its wall arranged at different elevations, whereby gas and liquid will be discharged through said passages according to the liquid level within said hollow member, and means for introducing a regulable quantity of gas into the upper portion of the interior of said hollow member to displace a portion of the liquid therein.

16. In apparatus for treating liquids with gases, a tank adapted to contain a liquid, a permeable surface having a circular periphery and continuity of surface concentric with the peripherv and having a multiplicity of gas passages arranged at various distances from a vertical axis suspended within the tank and submerged in the liquid, means for forcing a gas through the gas passages of the permeable surface into the liquid, andmeans arranged for rotating the permeable surface concentrically about an axis having the central line of the permeable surface as the center of rotation.

17. In apparatus for separatingminerals from their gangue by flotation, a permeable surface having a circular periphery suspended within the tank and-submerged in the liquid, means for passing a gas through the permeable surface, and means for feeding the material to be treated near the center of rotation to pass over the permeable surface toward the periphery.

18. In flotation apparatus, a tank adapted to contain a liquid, a rotatably mounted permeable surface having a circular periphery and continuity of surface concentric. with the periphery and having a multiplicity of gas passages arranged at various distances from the center of rotation suspended within the tank'and submerged in the liquid, means arranged for passing a gas through the gas passages in the permeable surface into the liquid above it, means for rotating the permeable surface about its vertical axis, and means arranged for passing the material to be treated across the path of the ascending atomized gas.

19. In apparatus for treating liquids with gases, a tank adapted to contain a, liquid, a rotary atomizer suspended within the tank and submerged in the liquid, said atomizer having a circular periphery and having gas passages extending from its interior central portion toward its periphery and arranged with outlets at various distances from the center of rotation, means for causing a flow of gas to theinterior of the atomizer, and

means arranged for ejecting the gas from and having gas passages with outlets arranged at various distances from the center of rotation suspended within the tank and submerged in the liquid, means for introducing compressed gas into the tank and by the buoyancy of the gas passing it through I the gas passages 1n the rotary member, means for rotating the rotary member about its vertical axis, and a liquid outlet arranged so as to cause a flow of liquid toward the 10 outlet in a direction opposite to that of the ascending atomized as in the liquid.

WILLIAM .GREENAWALT'. Witnesses:

Amos B. Ross, CORA M. .GREENAWALT. 

